Ash monitor and overcharge protection control system for incinerator

ABSTRACT

This disclosure is directed to an electromechanical control system by which the routine day to day operation of an incinerator is protected from certain hazards commonly associated with incinerator operation. The control system provides for automatic opening of a charging door when an operator approaches to insert burnable refuse, and for holding the charging door open while the operator is charging the incinerator. Provision is also made for limiting the total time during which the operator may engage in charging refuse into the incinerator. After this limited total time expires, the charging door, upon closing, will remain positively closed for a definite predetermined period of time to minimize explosion hazards in the event explosive objects, such as pressurized cans and stoppered bottles, are inadvertently charged into the incinerator. Provisions are also made for prohibiting firing of the incinerator unless the ashes are removed at the end of a predetermined period of incinerator operation, e.g., at least once every 24 hours. The arrangement is such that the incinerator is rendered inoperative for a predetermined period of time upon the opening of the ash removal door so as to provide for complete ash removal before operation can be resumed.

United States Patent Spencer is] 3,682,l 16

1451 Aug. 8, 1972 [s41 ASH MONITOR AND OVERCHARGE PROTECTION CONTROLSYSTEM FOR INCINERATOR [72] Inventor: Paul W. Spencer, Morris Plains,NJ.

[73] Assignee: Northeast Burn-Z01 Corporation,

' Dover, NJ.

221 Filed: m.14,197o

21 Appl.No.: 97,577

521 U.S.Cl. ..ll0/8R,1l.0/176 51 1111. C1. ..F23g 5/00 [58]FieldolSearch ..uo/s,1s R, 18 E, 173, 176,

- [56] References Cited UNITED STATES PATENTS 2,960,046 11/1960 Clark..110/173 X 3,141,426 7/1964 Zachow ..110/18 3,196,814 7/1965 Hahn eta1. ..110/18 3,330,231 7/ 1967 Spencer ..1 10/18 PrimaryExaminer-Kenneth W. Sprague Attorneylrving Seidman s71 ABSTRACT Thisdisclosure is directed to an electromechanical control system by whichthe routine day to day operation of an incinerator is protected fromcertain hazards commonly associated with incinerator operation. Thecontrol system provides for automatic opening of a charging door when anoperator approaches to insert bumable refuse, and for holding thecharging door open while the operator is charging the incinerator.

Provision is also made for limiting the total time during which theoperator may engage in charging refuse into the incinerator. After thislimited total time expires, the charging door, upon closing, will remainpositively closed for a definite predetermined period of time tominimize explosion hazards in the event explosive objects, such aspressurized cans and stoppered bottles, are inadvertently charged intothe incinerator.

Provisions are also made for prohibiting firing of the incineratorunless the ashes are removed at the end of a predetermined period ofincinerator operation, e.g., at least once every 24 hours. Thearrangement is such that the incinerator is rendered inoperative for apredetermined period of time upon the opening of the ash removal door soas to provide for complete ash removal before operation can be resumed.

19 Claims, 8 Drawing Figures PATENTEDAU: a 1912 sum 1 or 5 AT TORNEYmsmenws 1m SHEET 2 BF 3 INVENTOR. PRUL W. SPENCER A BY ATTORNE YPATENTEMI: 8l972 3.682.116

sum 3 or 3 m @E w @I m @E m @I INVENTOR. P/IUL 14/; SPENCER W B G s m MNQ5 Q0 om V 1 A 1% 02 \W mm my mm .NN 8% NS 0% 09.03

02 02 m.N m

E St $535 2:2;

A 7' TORNE Y ASH MONITOR AND OVERCHARGE PROTECTION CONTROL SYSTEM FORINCINERATOR PROBLEMS AND PRIOR ART Poor operation of manually chargedincinerator is generally attributed to overcharging and/or failure toremove the ashes. Overcharging results in throttling the circulation ofcombustion air which slows up the buming process. Failure to removeashes results in ash accumulations which tend to reduce chamber volumeand thereby inhibit burning. Also as the level of ash becomesprogressively higher and higher above the bottom of the incinerator, thelevel of the fire eventually approaches the level of the charging doors.In such event hazardous items such as pressurized cans and stopperedbottles, if mistakenly charged into the furnace can explode. If suchexplosion occurs as the furnace door is open when an operator ischarging the furnace, the operator can be seriously injured as a resultthereof.

OBJECTS It is an object of this invention to provide an incineratorcontrol system which will limit the amount of charge an operator mayinsert at any one time.

Another object is to provide a control system which will require a waitof a predetermined time interval after charging before additional refusecan be inserted into an incinerator.

Another object is to provide a control system which will render anincinerator inoperative if ashes have been allowed to accumulate for anexcessive period of time, e.g., 24 hours.

Another object is to provide a control system which will automaticallyopen an incinerator charging door as an operator is about to charge theincinerator.

Another object is to provide a control system which will prohibitincinerator operation for a predetermined time interval to provide forcleaning out of ashes.

Another object is to provide an incinerator control system which willinhibit the closing of a charging door if an operator happens to be inthe act of loading refuse.

BRIEF SUMMARY OF INVENTION The foregoing objects, and other features andadvantages are attained by a control system for an incinerator or thelike which includes an ash monitoring and overcharge protection system.The system includes an overcharge protection monitor having a singlecycle charge programmer comprising a plurality of cam wheels mounted ona common shaft actuated by an electrical motor. This programmer is setto make one revolution in a predetermined time interval to provide forthe charging and overcharge protection features of the invention. Inconjunction with this programmer, there is provided a first micro-switchwhich is actuated by the weight of an operator as he stands on a floormat adjacent the incinerator charging door. There is also provided inthe circuit a first starting solenoid which starts the programmerthrough its cycle, and a first safety relay which protects an operatorwho happens to be standing on the loading mat at the time the chargedoors are to automatically close.

The system also includes a 24 hour time clock which emits a 12 minutepulse after 24 hours of running. This time clock pulse triggers theoperation of a shut down programmer. The shut down programmer, like thecharge programmer, comprises a plurality of cam wheels mounted on asingle shaft turned by an electric motor. Associated switches in thisprogrammer, operated by the cams, enable the programmer to shut down theincinerator by disabling theoperation of the charging door. A part ofthe system includes a second micro-switch which is closed and opened bythe operation of the incinerators ash door. There is also an ash doorrelay which turns over control of the shut down programmer to the ashdoor during shut down. Finally there is a second safety relay which alsois part of this system to cause the shut down programmer to be stoppedin its cycle if an operator happens to be in the act of loading refusewhen the cycle begins. The system is arranged so that when an operatorceases loading and moves off the loading mat the programmer resumes itsrundown for ash removal.

FEATURES A feature of this invention resides in the combination of afloor mat utilized in circuit with a programmer to control the openingof an incinerator charging door whenever an operator steps on the mat toeffect charging of the incinerator.

Another feature of this invention resides in the provision of aprogrammer to limit a maximum opening time of fixed duration for anincinerator charging door after which time the charging door will notopen for a predetermined time period.

Another feature of this invention resides in the provision of aprogrammer to render the charge door open ing mechanism inoperative fora fixed period of time during which no further charge may be inserted.

Another feature of this invention resides in safety circuits whichprevent an incinerator charging door from closing if an operator happensto be standing on the mat charging the incinerator.

Another feature of this invention resides in the combination of a timerwith a shut down programmer to render the incinerator inoperative whenashes have been allowed to accumulate for a predetermined period.

Another feature of this invention resides in safety circuits to preventthe incinerator charging door from closing in response to a shut downsignal if an operator is in charging position on the mat.

Another feature of this invention resides in electrical circuits whichaccumulate the time during which an ash door is in an open position sothat the incinerator may not be put back into service prematurely.

Other features and advantages will become more readily apparent whenconsidered in view of the specification and drawing in which:

FIG. 1A represents a schematic showing of an incinerator embodying theinvention.

FIG. 1 is a schematic circuit diagram of the control system of thisinvention.

FIG. 2 is a profile view of a cam 1-3 which comprises part of the chargecontrol programmer P-l.

FIG. 3 is a profile view of a cam 1-2 which comprises another part ofthe charge control programmer P-l.

FIG. 4 shows a profile view of a cam 2-3 which comprises part of theshut down programmer P-2.

FIG. 5 shows a profile view of a cam 2-2 which comprises another part ofthe shut down programmer P-2.

FIG. 6 is a timing diagram for the shut down programmer P-l which showsthe relative open and closed times of switch SW6 and switch SW7 on theprogrammer P-l.

FIG. 7 is a timing diagram for the charge control programmer P-2 showingthe relative open and closed times of switches SW3 and SW5 on theprogrammer P-2.

DETAILED SPECIFICATION Referring to the drawing there is shown in FIG.1A, a typical incinerator I for burning waste and/or refuse or the like.It comprises a furnacearea F into which the refuse or waste is chargedfor burning. Access to the furnace is afforded through a charging door Dwhich is operatively connected to an actuating means 2 for effecting itsopening or closing. The actuating means 2 may comprise a piston andcylinder assembly, an electric motor or other suitable operator which isactuated by a switch means 1 located on a floor mat M located adjacentthe charging door, and which switch means 1 is actuated by the weight ofan operator standing on the charging mat; as will be hereinafterdescribed. The incinerator I also includes an ash clean-out door Aadjacent the bottom of the furnace through which the ash pit may becleaned out. As will be hereinafter described the ash door A isoperatively associated with a portion of the control system to prohibitoperation of the incinerator unless the ashes are periodically cleanedout of the ash pit.

Burnable refuse is manually loaded into the incinerator I by an operatorwho is required to step onto a mat M located on the floor just in frontof the incinerators charging door D. The floor mat M includes amicroswitch SW1 (FIG. 1), actuated by the weight of the operator, whichin turn delivers electrical energy to the charging door actuator 2comprising an electro-pneumatic or other suitable actuator for openingor closing the charging door D. When an operator steps on the mat M, themicro-switch SW1 is closed, and thus completes an electrical circuitthrough appropriate electrical leads 3, 4, 5 to the door actuator 2.Located in the circuit also are switches, SW5, and SW6 which arenormally closed at the start of the loading cycle and which will beexplained later. By completion of the foregoing circuit to the dooractuator 2 the charging door D opens to permit insertion of refuse. Whenpower to the charging door actuator 2 ceases, the door, beingself-closing, returns by itself to a closed position.

An overcharge protection circuit is provided and it is renderedoperative when the operator first steps on the mat M. Closure of themats micro-switch SW1 by the operators weight energizes, throughappropriate leads 6, 7 from a 24 volt source 8, an enabling relay R5which closes its normally open contacts 23. Contacts 23 when closedcomplete an electrical circuit from a 115 volt source 9, through otherleads 10, 21, l9, 18 to a first starting solenoid S1. Starting solenoidSl completes a separate circuit through its own normally open contacts14, which are now closed, and through electrical leads 15, 16, 17, l8,19, 22, to deliver 115 volt power to a drive motor 31 that turns anovercharge programmer P1. The overcharge programmer Pl commences turningfor a single cycle time period, e. g., for 4 minutes and 30 seconds.During this time the operator is enabled to insert refuse for acumulative total of seconds, and then he is required to wait for 3additional minutes before any further loading.

Control of the programmer P1 as well as the loading and subsequentwaiting periods is afforded by a cluster of three cams 1-1, 1-2, 1-3which are mounted on a common shaft 30 that is turned by the programmermotor 31.

One of the three cams is a cycling cam I-l which is providedspecifically for controlling the programmer Pl itself. Thestartingsolenoid S1 is of the latching type. Therefore, once it isenergized, its relay contacts 14 remain closed even after electricalpower to the solenoid S1 is interrupted. But the cycling cam l-lmechanically opens the contacts 14 of the starting solenoid S1 when theprogrammer P1 has completed its cycle by turning through an angulardisplacement of 360. With the electrical energy to the programmer motor31 thus interrupted, the programmer P1 stops.

A charging control cam l-3, the rotation of which is identical in timeand duration with the cycling cam l-l governs the duration of theloading and waiting periods of the incinerator. FIG. 2 shows the profileof the charge control cam 1-3 which has an indented or notched portion32 of angular degrees and a raised portion 33 of 240 angular width. Thespeed of the programmer motor 31 is such that the cam cluster requires apredetermined elapsed time to turn through the first 120 and anadditional predetermined lapsed time to turn through the remaining 230.In the illustrated embodiment a complete cycle of 360 is set so as torequire a total elapsed time of 4 minutes and 30 seconds. 90 seconds forthe first 120 and 3 minutes for the other 240. Referring again to FIG.1, it may be seen that there is a normally open charging switch SW6 inthe electrical circuit to the charging doors power pack or actuator 2.This switch SW6 is mechanically moved between its open and closedpositions by the charging control cam 1-3. When the programmer P1 is atrest, prior to beginning a loading cycle, the charging switch SW6 restson the raised portion 33 of the charging cam 1-3, at the spot designatedby the arrow A1 in FIG. 2. As the programmer motor 31 begins to turn thecam 1-3 in the clockwise direction, due to the operators havinginitially stepped on the floor mat M, the indented portion 32 of thecharging cam l-3 comes under the switch SW6. This causes contact 34 toclose. In FIG. 1, it may be seen that this completes the electricalcircuit from the 24 volt source 8 to the charging door actuator 2causing the charging door to open. Unless otherwise interrupted, theprogrammer Pl will continue turning and 90 seconds later, the raisedportion 33 of the cam 1-3 will come under the charging switch SW6causing it to open its contacts 34. Upon being opening, the chargingswitch SW6 interrupts the electrical energy to the charging dooractuator 2 and the door will close to begin the 3 minute waiting period.Should the operator step on the floor mat again during the 90 secondloading period, the charging door will reopen. During the subsequentwaiting period of 3 minutes, however, the charge control cam 1-3 willturn through its remaining 240 of angular displacement, and keep thecharging switch SW6 open. Because the charging switch SW6 is nowinterrupting the circuit to the actuator 2 no amount of stepping on thefloor mat can cause the charging door to re-open.

A safety cam 1-2 provides protection for the operator, should he happento be on the floor mat M in the act of loading refuse when the end ofthe 90 second loading period occurs and the charging door is ready toclose. FIG. 3 illustrates the profile of the safety cam 1-2. With araised portion 34 of approximately 352.8 angular width and an indentedportion 35 of 7.2", the cam 1-2 is able to mechanically open and close asafety switch SW7 (See FIG. 1) which rides on the cam 1-2. In FIG. 3, anarrow Bl shows where on the cam 1-2 the safety switch SW7 rests at thestart of the loading cycle. This safety switch SW7, acting inconjunction with the floor mats micro-switch SW1 stops the chargeprogrammer Pl before it calls for the charging-door D to close. Thecharging door D is thereby prevented from closing until the operatorgets off the mat and the proglrammer Pl allowed to resume turningthrough its cyc e.

This safety precaution is made possible by the relative timings of thesafety cam 1-2 and the charging control cam 1-3 and by a safety relayR4. The safety relay R4 is controlled by the safety cam l-2 and in turncontrols normally closed contacts 36 in the electrical circuit thatdrives the programmer P1. The configuration of the safety cam l-2 isdesigned to close the safety switch SW7 after the programmer P1 hasturned for an elapsed time of say 87.3 seconds following thecommencement of the loading cycle. This timing is intended to occurbefore the charging control cam l-3 can terminate the 90 second loadingcycle.

FIG. 6 is a timing diagram showing when the two cams 1-2, 1-3 open andclose their respective switches SW6, SW7. The closing of the safetyswitch SW7 energizes the safety relay R4 through leads 10, 18, 20, 21 byconnecting it with the 115 volt power source 9. By opening its contacts36 the safety relay R4 interrupts the electrical power to theprogrammers motor 31. The result is to stop the programmer P1 2.7seconds before the charge control cam 1-3 can open the charging switchSW6. The end of the 90 second loading cycle is, therefore, not reached.Since the charging switch SW6 does not interrupt the power to thecharging door actuator 2 the charging door D does not close.

However, when the man gets off the mat, the microswitch SW1 opens andthe enabling relay R5 de-energizes and opens its contacts 23. Thecircuit to the safety relay R4 is also opened, and R4 de-energizes, thusallowing its contacts 36 to close. With the circuit to the programmermotor 31 thus restored, the programmer P1 will resume turning for thebalance of its cycle.

The control system further contemplates rendering the incineratorinoperative to accept further refuse or waste after a predeterminedperiod of operation, eg 24 hours. This feature is provided so as toinsure that an operator will clean out the ash pit to effect removal ofthe ash to insure optimum incinerator operation.

This is attained by including in the circuit (FIG. 1) a timer, e.g., a24-hour clock T1. The timer T1 is a continuously running clock whichwill emit an electrical impulse of a predetermined duration, e. g., 12minutes or another suitable period. This impulse is utilized to start ashut down programmer P2 which prohibits any further loading ofadditional refuse into the incinerator. Subsequent start up will occuronly if ashes are removed, and a predetermined time interval is providedto effect the ash removal. Generally 30 minutes has been found to besufficient time to effect this ash removal. Through appropriateelectrical leads 40, 41, the 12 minute pulse is delivered to a secondstarting solenoid S2 which, by closing its contacts 43, permits theenergizing of a shut down programmer motor 44. The programmer motor 44is powered from a volt source 9 through separate electrical leads 45,46, 47. In the motor circuit are certain other series connected relaycontacts 70, 52. Since these other contacts 70, 52 are normally closed,they do not interfere with the starting of the programmer P2 when theshut down cycle is initiated.

Additional loading of refuse is prohibited by rendering the dooractuator 2 inoperative. Programmer P2 accomplishes this. As previouslydescribed, the charging door actuator 2 receives electricity from a 24volt source 8 through its electrical leads 3, 4, 5, 48, 49. In thiscircuit is a single pole double throw electrical switch SW5 that ismechanically transferable between its two alternate positions by a shutdown cam 2-3. This cam is one of three cams mounted on a common shaft 50this is turned by the shut down programmers motor 44. When theprogrammer P2 is at rest, and at the beginning of its cycle, thetransfer switch SW5 is normally closed to make a complete circuit todeliver 24 volt power to the charging doors opening mechanism. Thecircuit is made by electrical leads 3, 4, 5, 48, 49 which connect thetransfer switch SW5 and the microswitch SW1 in series with the actuator2. After the programmer P2 has started and has turned through say, 5l.5of its total rotation, the transfer switch SW5 is transferred by theshut down cam 1-3 to close its normally open contact, and the electricalsupply to the actuator 2 is interrupted. With no power supply, thecharging door D closes and remains closed to prohibit any furtherloading.

In its transferred position the transfer switch SW5 also stops theprogrammer P2 and confers on the incinerators ash door A subsequentcontrol of the programmer P2. Through leads 53, 51 which previouslycarried no electricity, the transfer switch SW5 now connects an ash doorrelay R1 to the 24 volt source 8 of power. The contact 52 of this relayR1 are normally closed and although they are in the circuit that powersthe programmer P2 they do not at first interfere therewith. Upon theenergizing of the ash door relay R1, however, these contacts 52 open andstop the programmer P2 by interrupting its electrical supply. Amicro-switch SW2, operated by the ash door is connected by its own leads55, 54 to bridge the normally closed contacts 52 of the ash door relayR1. Therefore, even though the ash door relay contacts 52 have beenopened by the action of the transfer switch SW5, they can be shortcircuited by the ash door micro-switch SW2. The ash door micro-switchSW2 is ordinarily open when the ash door is in a closed condition butcloses to complete the programmer motor circuit when the ash door isopened. Thus, once the ash door relay R1 opens its contacts 52, theprogrammer P2 stops and will advance in its cycle only if the ash dooris kept open.

The ash removal is monitored by the shut down cam 2-3. In theillustrated embodiment of the invention this cam is designed to providea minute preparation period followed by a 30 minute shut down period.FIG. 4 shows the profile of the shut down cam 2-3 and the arrow C1indicates the point of the cam 2-3 on which the transfer switch SW5rests at the beginning of the shut down cycle. The cam 2-3 has anindented portion 60 of 5 angular width. While this indented portion 60is under the transfer switch SW5, the transfer switch SW5 is in itsnormal position. In this position it electrically connects certain leads48, 49 in order not to interfere with the electrical circuit to thecharging door actuator 2. However, the switch SW5 is transferred when anunindented portion 61 comes under it and thereby disables the power packcircuit.

Upon being started by the aforesaid 12 minute pulse, the programmer P2requires 5 minutes to turn the shut down cam 2-3 through the indentedportion 60 of its periphery. This 5 minute period provide a protectionfor the incinerator operator should he happen to be in the act ofloading refuse at the time the shut down cycle begins. At the end of theinitial 5 minute period the unindented portion 61 of the shut down cam2-3 comes under the transfer switch SW5 thus causing it to transfer itscontacts and thereby to commence the actual shut down of theincinerator.

The ash door must be kept open for a cumulative total of at leastminutes. This is because 30 minutes are required for the shut downprogrammer P2 to finish turning the shut down 2-3 through the balance ofthe ash removal cycle. After the cam 2-3 has been turned for a totalperiod of minutes, the indented portion 60 of the cams periphery willagain come under the transfer switch SW5 and cause the contacts toretransfer back to their original position. In this way, the circuitthrough the transfer switch SW5 to the charging door actuator 2 is againcompleted and the charging door D may be reopened for loading.

This same re-transfer, simultaneously deprives the ash door A of itscontrol over the incinerator. The circuit to the ash door relay R1through its lead 53 is broken and its contacts 52 return to theirnormally closed condition. With the electrical circuit'through its leads62, 63 restored, the shut down programmers operation no longer dependson the open or closed condition of the ash door.

With the completion of the shut down cycle and resumption of chargingdoor D operations the pro grammer P2 is required to come to a stop. Thepurpose is so that the programmer P2 will be ready for the next shutdown cycle 24 hours later. The programmer control cam 2-1 (not shownseparately) automatically stops the programmer P2 by mechanicallyunlatching the starting solenoid S2 contacts 43 when the cam cluster hasbeen turned by the programmer motor 44 a total of 360. With itselectrical supply interrupted the motor 44 can no longer turn the shutdown programmer P2.

A protective feature is required for the operator, should he happen tobe standing on the loading mat M, when actual shutdown is about tooccur. The automatic closing of the charging door D is prevented by asafety cam 2-2, shown in FIG. 5, which is mounted on the programmersshaft 50 along with the shut down cam 2-3 and is rotated at the sametime and at the same speed. A safety switch SW3 is mechanically operatedby the safety cam 2-2. This switch SW3 is placed in the circuit 10, ll,12, 71 of a safety relay R2 which has normally closed contacts 70.Through appropriate leads 13, 71, 12, 11, 10 closure of the safetyswitch SW3 by the safety cam 2-2 delivers 1 15 volt power to the safetyrelay R2 which then opens its own contacts 70. These contacts are in thepower circuit to the shut down programmer P2 and, by opening, will causethe programmer motor 44 to stop. An arrow D1 in FIG. 5 shows the spot onthe safety cam 2-2 on which the safety switch SW3 rests at the beginningof the shut down cycle. The cam 2-2 has an indented portion 73 that isof 72 angular width and which is located on the periphery of the camwhere it will come under the safety switch 4 minutes and 29 secondsafter the programmer P2 has begun turning through the shut down cycle.The significance of this timing may be better understood by referring toFIG. 7 which is a diagram showing the relative times of operation of theshut down switch SW5 and the safety switch SW3. The contacts of thesafety switch SW3 are normally open but they close when the indentedportion 73 of the safety cam 2-2 passes under the safety switch SW3.This event occurs earlier than the transfer of the shut down switch SW5which is scheduled to operate at 'the end of 5 minutes after the shutdown programmer P2 starts turning. An operator, standing on the mat M,closes the micro-switch SW1 and energizes the enabling relay R5 therebyclosing its contacts 23. With a circuit this completed throughconnecting leads 11, 12, volt power is supplied through the now closedsafety switch SW3 to energize the safety relay R2. Upon being energizedthe safety relay R2 opens its normally closed contacts 70 to break thecircuit to the programmer P2. With the power shut off, the programmer P2stops and the shut down cycle may not continue until the operator getsofi' the mat.

It will be understood that the time intervals herein set forth aremerely illustrative as they can be changed by altering the shape of thecams accordingly.

While the instant invention has been described with respect to aparticular embodiment thereof it will be readily understood andappreciated that variations and modifications may be made withoutdeparting from the spirit or scope of the invention.

What is claimed is:

1. In combination, a combustion chamber having a charging door and anash removal door, and

a control means including an actuator for effecting the operation ofsaid charging door,

switch means connected in circuit with said actuator located adjacentsaid charging door adapted to be activated by the weight of an operatorwhen charging said chamber,

a programmer operatively connected to said switch means and dooractuator to render said actuator operative for a predetermined timeinterval in response to the actuation of said switch means and to rendersaid actuator inoperative for a predetermined time interval upon theclosing of said charging door upon the lapse of said operative intervalof time.

2. The invention as defined in claim 1 and including a safety interlockmeans to prohibit the closing of said charging door in the event saidswitch means is maintained activated at the lapse of said operativeinterval of time.

3. The invention as defined in claim 2 and including a second programmermeans operatively associated with said ash door and said charging doorto measure the elapsed time since the last previous opening of the ashdoor.

4. The invention as defined in claim 3 wherein said latter means emit asignal upon sensing said predetermined lapsed time since the lastprevious opening of the ash door,

and means responsive to said signal to prohibit the opening of saidcharging door for a predetermined time interval necessary to effect ashclean out.

5. The invention as defined in claim 4 and including a second interlocksafety means to stop the run down of said second programmer means if anoperator is in the act of charging said chamber at the end of saidelapsed time since the last previous opening of the ash door.

6. The invention as defined in claim 1 wherein said switch meansincludes a mat located in front of the charging door, and said matincluding a switch for activating said door actuator during run down ofsaid programmer means during said operative time interval.

7. The invention as defined in claim 4 and including means to restorethe opening of said charging door,

said restoration means being controlled by the opening and closing ofsaid ash door.

8. In combination, a combustion chamber having a charging door and anash clean-out door, and

an actuator for opening and closing said charging door,

an overcharge protection circuit operatively connected to said dooractuator,

said overcharge protection circuit including a switch means actuated bythe weight of an operator,

a programmer means including a starting means that is actuated when saidswitch means is actuated,

said programmer means including means for rendering said actuatoroperative for a predetermined charging time interval each time saidswitch means is activated during said charging interval,

and said programmer including means for rendering said door actuatorinoperative for a predetermined non charging time interval upon thelapsing of said charging time interval.

9. The invention as defined in claim 8 wherein said programmer meansincludes:

a safety interlock means to maintain said charging door in the openposition in the event said operator is activating said switch means atthe end of said charging time interval. I

10. The invention as defined in claim 8 and including an ash monitormeans.

1 l. The invention as defined in claim 1 1 wherein said ash monitormeans includes:

a timing means to measure the elapsed time since the last previousopening of the ash removal door,

said timing means emitting a signal upon sensing said elapsed time sincethe last previous ash cleaning,

and means responsive to said signal to prohibit the opening of saidcharging door to prevent further charging of the combustion chambervuntil the ashes have been removed.

12; The invention as defined in claim 11 and including means to restorethe opening of the charging door upon the removal of the ashes; saidrestoration means being controlled by the opening and closing of saidash door.

13. The invention as defined in claim 11 wherein said latter meansincludes a shut-down programmer including means to stop the run down ofsaid shut-down-programmer in the event an operator is charging saidchamber with the charging door in the open position.

14. A system for monitoring ash accumulation in an incinerator, havingan ash removal door and a charging door, comprising:

means to emit a shut-down signal at periodic time intervals,

means responsive to said signal to disable opening of the charging door,

means to record the length of each time the ash door remains in an openposition during said periodic time interval,

means for accumulating successive periods of ash door open time wheresaid open time is interrupted one or more times by closing of the ashdoor,

means for emitting a restoring signal when ash door open timesaccumulate to a predetermined quantum of time, and

means responsive to said restoring signal to restore operation of thecharging door.

15. A safety system to provide a limited charging time followed by amandatory waiting period of predetermined duration during. whichcharging is prohibited in an incinerator have a closable charging doorcomprising:

actuating means for moving said charging door between its open andclosed positions,

an electric circuit including a first source of electrical power,

a switch means disposed in said circuit so as to be actuated by anoperator who is charging said incinerator with refuse,

a charging programmer having a shaft and an electric motor driving theshaft at a predetermined angular speed, charging cam mounted on saidshaft to rotate therewith, and having a peripheral surface containing anindent of constant radius and of predetermined angular width, and araised portion of constant radius and predetermined angular width,

a charging electrical switch riding on the periohery of said chargingcam wheel so that the switch'is closed when it rides on the indent andis open when it rides on the raised portion of the cam wheel whereby thebeginning of the indent is initially under the charging switch,

said micro-switch, actuator, and the charging switch being connected inseries in said circuit,

a second power source,

a latching type electrical switch,

a solenoid adapted to close said latching switch when the solenoid isenergized, whereupon said latching switch will latch in a closedposition regardless of loss of power to the solenoid,

an enabling relay having a single pair of normally open electricalcontacts,

electrical leads connecting the enabling relay in series with themicro-switch in the low voltage circuit, but in parallel with the seriescombination of actuating means and cam-operated charging switch,

said latching contacts and the electric motor being connected in serieswith said second source of power, and

said enabling contact and the starting solenoid being connected inseries with said second source of power,

a cycling cam mounted on the shaft to turn with the charging cam wheel,and adapted to mechanically unlatch the contacts of the startingsolenoid to open the contacts after the shaft has made one completerevolution.

16. In the incinerator safety system of claim 15 including means todelay the start of the non-charging period, if an operator is insertingrefuse at the termination of the charging period,

said delay means including:

a safety cam mounted on the programmer shaft to turn with the cyclingcam and the charging cam, and having a peripheral surface containing anindent of constant radius of predetermined angular width, and having anunindented portion of constant radius-and predetermined angular width,

a safety switch riding on the periphery of the safety cam and mounted sothat the safety cams indent mechanically moves the switch into itsclosed position not more than a few seconds after the programmer motorbegins to turn through its cycle, and to open position not less than afew seconds after the programmer begins to turn through its cycle,

a safety relay having a normally closed pair of contacts,

electrical leads connecting the safety switch and the safety relay inseries with the second power source, and

electrical leads connecting the normally closed contacts of the safetyrelay, the latching contacts and the programmer motor in series withsaid second source of power, so that when the safety cam opens thesafety switch, the second source of power is interrupted and theprogrammer motor stops in its cycle, until the incinerator attendantallows the micro-switch to open.

17. A system for monitoring ash accumulation in an incinerator having acharging door for charging, comprising:

an actuator for moving the charging door between its open and closedpositions, a source of low voltage electrical power, e.g., 24

volts,

a mat switch means disposed as to be closed by an incinerator attendantduring charging of the incinerator with refuse,

a shut down programmer having a motor shaft adapted to make onerevolution in a predetermined time interval,

a shut down cam mounted on the shaft and having a peripheral surfacewith an indent of contant radius and predetermined angular width and aremaining unindented portion of constant radius,

a transfer switch having normally closed contacts and normally opencontacts riding on the periphery of the shut down cam so that thenormally closed contacts of the switch are closed when the indent isunder the switch and open when the unindented portion is under theswitch, said transfer switch being disposed so that at the beginning ofthe shut down cycle the indent portion of the cam comes under theswitch,

electrical leads connecting the charging door, actuator, the mat switch,and the normally closed contacts of the transfer switch in series withthe low voltage power source,

a high voltagesource of electrical power, e.g.,

volts,

an electrical clock timer adapted to be driven by the 1 15 volt powersource, and having electrical output terminals at which thereisavailable periodically an electrical voltage pulse of predeterminedduration, said pulse occurring at the expiration of each successive 24hours following the commencement of the most recent previous pulse,

a second starting solenoid having normally open contacts which areadapted to latch in a closed position when electrical power is suppliedto the solenoid, said solenoid being capable of closing its contacts ina latched position in response to the electrical pulse from the timer,

electrical leads connecting the second starting solenoid to the outputterminals of the timer,

electrical leads connecting in series, the programmer motor, thenormally open solenoid contact and the second power source, and

a cycling cam mounted on the programmer shaft to turn integrally withthe shut down cam, and adapted to mechanically unlatch the contacts ofthe starting solenoid to open the contacts after the shaft has made onecomplete revolution.

18. In an incinerator having a control system for monitoring ashaccumulation as defined in claim 17 including an ash door,

an ash door switch disposed as to be held in a closed position by theash door when the ash door is open, and in open circuit position whenthe ash door is shut,

an ash door relay having normally closed electrical contacts,

electrical leads connecting the ash door relay, the 24 volt power sourceand the normally open contacts of the transfer switch all in seriesrelation,

electrical leads connecting the normally closed contacts of the ash doorrelay in series relation with the series combination of programmermotor, normally open solenoid contact, and 115 volt power source, andelectrical leads connecting the ash door micro-switch in parallelrelation with the normally closed contacts of the ash door relay.

19. In an incinerator having a control system for monitoring ashaccumulation defined in claim 17 and including:

a personnel safety interlock comprising: a safety relay having normallyopen electrical contacts,

a safety cam mounted on the shut down programmer's shaft to turn at thesame angular speed and in the same direction of rotation as the shutdown cam, said safety cam having a peripheral serface with an indent ofa predetermined width and constant radius, and a remaining unindentedportion,

a normally open safety switch disposed as to be mechanically movablebetween its open and closed positions by the indent and unindentedportions of the safety cam, said safety switch being disposed as to beclosed when the indent comes under the switch at a predeterminedinterval after the programmer has commenced turning through 1 electricalleads connecting the normally open contacts of the enabling relay inseries relation with the series combination of the cam operated safetyswitch, the volt power source, and the safety relay.

1. In combination, a combustion chamber having a charging door and anash removal door, and a control means including an actuator foreffecting the operation of said charging door, switch means connected incircuit with said actuator located adjacent said charging door adaptedto be activated by the weight of an operator when charging said chamber,a programmer operatively connected to said switch means and dooractuator to render said actuator operative for a predetermined timeinterval in response to the actuation of said switch means and to rendersaid actuator inoperative for a predetermined time interval upon theclosing of said charging door upon the lapse of said operative intervalof time.
 2. The invention as defined in claim 1 and including a safetyinterlock means to prohibit the closing of said charging door in theevent said switch means is maintained activated at the lapse of saidoperative interval of time.
 3. The invention as defined in claim 2 andincluding a second programmer means operatively associated with said ashdoor and said charging door to measure the elapsed time since the lastprevious opening of the ash door.
 4. The invention as defined in claim 3wherein said latter means emit a signal upon sensing said predeterminedlapsed time since the last previous opening of the ash door, and meansresponsive to said signal to prohibit the opening of said charging doorfor a predetermined time interval necessary to effect ash clean out. 5.The invention as defined in claim 4 and including a second interlocksafety means to stop the run down of said second programmer means if anoperator is in the act of charging said chamber at the end of saidelapsed time since the last previous opening of the ash door.
 6. Theinvention as defined in claim 1 wherein said switch means includes a matlocated in front of the charging door, and said mat including a switchfor activating said door actuator during run down of said programmermeans during said operative time interval.
 7. The invention as definedin claim 4 and including means to restore the opening of said chargingdoor, said restoration means being controlled by the opening and closingof said ash door.
 8. In combination, a combustion chamber having acharging door and an ash clean-out door, and an actuator for opening andclosing said charging door, an overcharge protection circuit operativelyconnected to said door actuator, said overcharge protection circuitincluding a switch means actuated by the weight of an operator, aprogrammer means including a starting means that is actuated when saidswitch means is actuated, said programmer means including means forrendering said actuator operative for a predetermined charging timeinterval each time said switch means is activated during said charginginterval, and said programmer including means for rendering said dooractuator inoperative for a predetermined non charging time interval uponthe lapsing of said charging time interval.
 9. The invention as definedin claim 8 wherein said programmer means includes: a safety interlockmeans to maintain said charging door in the open position in the eventsaid operator is activating said switch means at the end of saidcharging time interval.
 10. The invention as defined in claim 8 andincluding an ash monitor means.
 11. The invention as defined in claim 11wherein said ash monitor means includes: a timing means to measure theelapsed time since the last previous opening of the ash removal door,said timing means emitting a signal upon sensing said elapsed time sincethe last previous ash cleaning, and means responsive to said signal toprohibit the opening of said charging door to prevent further chargingof the combustion chamber unTil the ashes have been removed.
 12. Theinvention as defined in claim 11 and including means to restore theopening of the charging door upon the removal of the ashes; saidrestoration means being controlled by the opening and closing of saidash door.
 13. The invention as defined in claim 11 wherein said lattermeans includes a shut-down programmer including means to stop the rundown of said shut-down-programmer in the event an operator is chargingsaid chamber with the charging door in the open position.
 14. A systemfor monitoring ash accumulation in an incinerator, having an ash removaldoor and a charging door, comprising: means to emit a shut-down signalat periodic time intervals, means responsive to said signal to disableopening of the charging door, means to record the length of each timethe ash door remains in an open position during said periodic timeinterval, means for accumulating successive periods of ash door opentime where said open time is interrupted one or more times by closing ofthe ash door, means for emitting a restoring signal when ash door opentimes accumulate to a predetermined quantum of time, and meansresponsive to said restoring signal to restore operation of the chargingdoor.
 15. A safety system to provide a limited charging time followed bya mandatory waiting period of predetermined duration during whichcharging is prohibited in an incinerator have a closable charging doorcomprising: actuating means for moving said charging door between itsopen and closed positions, an electric circuit including a first sourceof electrical power, a switch means disposed in said circuit so as to beactuated by an operator who is charging said incinerator with refuse, acharging programmer having a shaft and an electric motor driving theshaft at a predetermined angular speed, a charging cam mounted on saidshaft to rotate therewith, and having a peripheral surface containing anindent of constant radius and of predetermined angular width, and araised portion of constant radius and predetermined angular width, acharging electrical switch riding on the periohery of said charging camwheel so that the switch is closed when it rides on the indent and isopen when it rides on the raised portion of the cam wheel whereby thebeginning of the indent is initially under the charging switch, saidmicro-switch, actuator, and the charging switch being connected inseries in said circuit, a second power source, a latching typeelectrical switch, a solenoid adapted to close said latching switch whenthe solenoid is energized, whereupon said latching switch will latch ina closed position regardless of loss of power to the solenoid, anenabling relay having a single pair of normally open electricalcontacts, electrical leads connecting the enabling relay in series withthe micro-switch in the low voltage circuit, but in parallel with theseries combination of actuating means and cam-operated charging switch,said latching contacts and the electric motor being connected in serieswith said second source of power, and said enabling contact and thestarting solenoid being connected in series with said second source ofpower, a cycling cam mounted on the shaft to turn with the charging camwheel, and adapted to mechanically unlatch the contacts of the startingsolenoid to open the contacts after the shaft has made one completerevolution.
 16. In the incinerator safety system of claim 15 includingmeans to delay the start of the non-charging period, if an operator isinserting refuse at the termination of the charging period, said delaymeans including: a safety cam mounted on the programmer shaft to turnwith the cycling cam and the charging cam, and having a peripheralsurface containing an indent of constant radius of predetermined angularwidth, and having an unindented portion of constant radius andpredetermined angular width, a safety switch riding on the periphery ofthe safety cam and mounted so that the safety cam''s indent mechanicallymoves the switch into its closed position not more than a few secondsafter the programmer motor begins to turn through its cycle, and to openposition not less than a few seconds after the programmer begins to turnthrough its cycle, a safety relay having a normally closed pair ofcontacts, electrical leads connecting the safety switch and the safetyrelay in series with the second power source, and electrical leadsconnecting the normally closed contacts of the safety relay, thelatching contacts and the programmer motor in series with said secondsource of power, so that when the safety cam opens the safety switch,the second source of power is interrupted and the programmer motor stopsin its cycle, until the incinerator attendant allows the micro-switch toopen.
 17. A system for monitoring ash accumulation in an incineratorhaving a charging door for charging, comprising: an actuator for movingthe charging door between its open and closed positions, a source of lowvoltage electrical power, e.g., 24 volts, a mat switch means disposed asto be closed by an incinerator attendant during charging of theincinerator with refuse, a shut down programmer having a motor shaftadapted to make one revolution in a predetermined time interval, a shutdown cam mounted on the shaft and having a peripheral surface with anindent of contant radius and predetermined angular width and a remainingunindented portion of constant radius, a transfer switch having normallyclosed contacts and normally open contacts riding on the periphery ofthe shut down cam so that the normally closed contacts of the switch areclosed when the indent is under the switch and open when the unindentedportion is under the switch, said transfer switch being disposed so thatat the beginning of the shut down cycle the indent portion of the camcomes under the switch, electrical leads connecting the charging door,actuator, the mat switch, and the normally closed contacts of thetransfer switch in series with the low voltage power source, a highvoltage source of electrical power, e.g., 115 volts, an electrical clocktimer adapted to be driven by the 115 volt power source, and havingelectrical output terminals at which there is available periodically anelectrical voltage pulse of predetermined duration, said pulse occurringat the expiration of each successive 24 hours following the commencementof the most recent previous pulse, a second starting solenoid havingnormally open contacts which are adapted to latch in a closed positionwhen electrical power is supplied to the solenoid, said solenoid beingcapable of closing its contacts in a latched position in response to theelectrical pulse from the timer, electrical leads connecting the secondstarting solenoid to the output terminals of the timer, electrical leadsconnecting in series, the programmer motor, the normally open solenoidcontact and the second power source, and a cycling cam mounted on theprogrammer shaft to turn integrally with the shut down cam, and adaptedto mechanically unlatch the contacts of the starting solenoid to openthe contacts after the shaft has made one complete revolution.
 18. In anincinerator having a control system for monitoring ash accumulation asdefined in claim 17 including an ash door, an ash door switch disposedas to be held in a closed position by the ash door when the ash door isopen, and in open circuit position when the ash door is shut, an ashdoor relay having normally closed electrical contacts, electrical leadsconnecting the ash door relay, the 24 volt power source and the normallyopen contacts of the transfer switch all in series relation, electricalleads connecting the normally closed contacts of the ash door relay inseries relation with the series combInation of programmer motor,normally open solenoid contact, and 115 volt power source, andelectrical leads connecting the ash door micro-switch in parallelrelation with the normally closed contacts of the ash door relay.
 19. Inan incinerator having a control system for monitoring ash accumulationdefined in claim 17 and including: a personnel safety interlockcomprising: a safety relay having normally open electrical contacts, asafety cam mounted on the shut down programmer''s shaft to turn at thesame angular speed and in the same direction of rotation as the shutdown cam, said safety cam having a peripheral serface with an indent ofa predetermined width and constant radius, and a remaining unindentedportion, a normally open safety switch disposed as to be mechanicallymovable between its open and closed positions by the indent andunindented portions of the safety cam, said safety switch being disposedas to be closed when the indent comes under the switch at apredetermined interval after the programmer has commenced turningthrough its shut down cycle, an enabling relay having normally openelectrical contacts, electrical leads connecting the enabling relay inseries relation with the ash door micro-switch, the safety switch andthe low voltage power source, and electrical leads connecting thenormally open contacts of the enabling relay in series relation with theseries combination of the cam operated safety switch, the 115 volt powersource, and the safety relay.